I always find it strange and amazing when animals behave in ways that make them look human. Check out the video of this ticklish koala. Besides being almost disgustingly cute, it's a perfect example of how some non-human animals can also manipulate their facial features to respond to physical contact and show emotion. You can't look at the koala's face and not instantly see its contentedness.
And one note of caution: this koala is obviously in a zoo situation and is used to being in close proximity to people and being touched. Never approach any wild animal, because even cute ones will not hesitate to bite and claw you to protect themselves. In fact, in the wild koalas have a reputation for being rather nasty when they feel threatened.